Electrical connectors are commonly used to terminate the end of an electrical conductor, such as a wire, for connecting the conductor to electronics or electric equipment. Moisture in electrical connectors may cause electrical shorts or degrade the connector materials through oxidization, establishing a galvanic cell, or other mechanism which degrades the quality of electrical connections within the electrical connector. Fires or other hazardous conditions may result, or the electrical connector may fail to properly conduct electricity or electric signals. Thus it is important to limit or prevent moisture ingress into electrical connectors in many applications.
Moisture may ingress into an electrical connector when the electrical connector is subjected to repeated air density changes. Air density changes occur when one or all of air temperature, relative humidity, and air pressure changes. Air temperature and relative humidity are meteorological phenomena, but can also be influenced by varying altitude above sea level. An increase in either temperature or humidity decreases the air density, and vice versa. Air pressure is also a meteorological phenomena, but is also heavily influenced by varying altitude above sea level. An increase in air pressure increases the air density, and vice versa.
When air is separated, for example a sealed chamber full of air with a first density placed in an atmosphere of air with a second density that is higher than the first density, air will move from the more dense region to the less dense region if given an opportunity such as a leaky seal. If dense air is able to move into an area containing less dense air, the dense air will bring any water vapor suspended in the dense air with it. Air density changes commonly occur in aircraft, and thus in electrical connectors mounted in aircraft. For example, an aircraft that descends from an altitude of 25,000 feet to sea level will contain electrical connectors filled with a lower density air than the surrounding atmosphere at sea level.
Common, current electrical connectors used in aircraft, such as part number 1877819-2 manufactured by Tyco Electronics Corporation of Menlo Park, Calif., United States, use a frontshell with a backshell adhered to the frontshell to form a moisture resistant seal. Such a backshell is commonly made from a rubber or other flexible heat-shrink material and is placed over a portion of the frontshell. Heat is applied to shrink the backshell and adhere the backshell to the frontshell. The present inventor has recognized that such heat-shrink backshells have several disadvantages such as requiring a high heat that may damage wires, solder joints, or other electrical conductors or components within the electrical connector. Additionally, heat-shrink backshells may release harmful fumes from the rubber or other flexible backshell material when heated; require a time consuming process to assemble; form a weak seal because of the complex shape of the heat-shrink backshell; or become brittle over time and break down, thus resulting in an ineffective moisture barrier by weakening or destroying any seal between the backshell and the frontshell.
The present inventor has recognized a need for a durable moisture ingress resistant connector suitable for use in environments where air density changes relatively frequently and rapidly, such as in aircraft traveling between sea level and 20,000 to 60,000 feet above sea level. The present inventor has also recognized a need for a durable moisture ingress resistant connector that is quickly assembled, forms a robust seal between a backshell and a frontshell, and is relatively easy to repair or replace. Some or all of the following embodiments may satisfy some or all of the above-described needs, or may satisfy other needs.